Heat exchanger or condenser



F. ST. CLAIR, JR.

HEAT EXCHANGER 0R CONDENSER.

APPLICATION FILED OCT. 9, I919 Patented July 25, 1922.

ontra PALMER ST. CLAIR, JR., OF NIAGARA FALLS, NEW YORK. ASSIGNOR- TO THE NITRO- GEN CORPORATION. OF PROVIDENCE, RHODE ISLAND, A CORPORATION OF RHODE ISLAND.

HEAT EXCHANGER 0R CONDENSER.

escapes.

Specification of Letters Patent.

Patented July 25, 1922.

To a whom it 'fll-(lfl/ concern.

Be it known that I, PALMER ST. CLAIR, J12, a citizen of the United States, residing at N'agara Falls, in the county of Niagara and State of New York, have invented certain new and useful Improvements in Heat Exchangers or Condensers, of which the following is a specification.

T his invention relates to the art of changing the temperature of fluids and more especially to a process-of and means for efiiciently exchanging heat between fluids; which fluids may be gaseous, or liquid, or mixtures of gas and liquid. That is to say the exchange of heat may be eiiected between any selected fluid,be it gaseous or liquid,and any other fluid desired.

It is particularly adapted to those gases and mixtures of gases which have high specific heats; and the invention may be employed to especial advantage in efi'ecting condensation of such gases or vapors to liquids.

The principal object of my invention is to increase the efliciency of the interchange of heat between fluid masses, whereby, as a subsidiary object, not alone to conserve energy. but also to permit of the employ ment of smaller, more compact, and less expensive apparatus than has hitherto been available for the accomplishment of a comparable purpose; taking into account the relative quantities of fluid to be handled and the number of calories of heatto be exchanged, per unit of time.

These and other objects ofmy invention will be hereinafter referred to and the novel steps of procedure and combinations .35 elements whereby said objects may be attained will be more particularly pointed out in the claims appended hereto.

in the accompanying drawing which Forms part hereof, l have exemplified a preferred form of apparatus of the character in question: but as l am aware of various changes and modifications which may be made herein. I desire only to be limited by the scope of the claims, broadly interpreted in the light of my disclosure.

Referring to said drawing. in which like characters designate like parts in the respective views;

The preferred apparatus comprises a series of U-shaped tubes or pipes 1, in each of which, as shown in Figures 2, 4 and 5, there is a similar but smaller pipe or tube 2; tubes 1 and 2 being held in spaced relationship by a wrapping 3 of wire or the like, which preferably is of such size as to contact with the inner wall of a given tube 1 and correspondingly engage the outer wall of the tube 2 within said given tube.

There is thus very simply constituted a spiral or helical passage 4, which extends down one leg of a given U-shaped heat exchanging element and up the other. A somewhat similar helical passage 5 is provided within the inner tube 2 of each of said U- shaped elements; passage 5 preferably being formed by a twisted strip or ribbon 6, the width of which is preferably substantially equal to the inner diameter of tube 2.

Tube 2 may be of iron or other heat conductive material; iron or steel being preferred on account of cheapness, except when the fluids to be passed through the device in contact with the respective parts thereof are of such a nature as to corrode or otherwise chemically react upon iron or the selected metal. In such case a heat conductive material is selected which will not be afiected or impaired by the fluid, or cause the introduction of an impurity into the latter.

Des'irably also, the twisted strips or ribbons 6 and coils 3 are also of heat conductive material, to favor the transfer of heat from passages 5 to passages 42. or vice versa, and the dissemination of such heat within the mass of the fluid being heated.

it the outer tubes 1 are made of iron or the like, they should be heat insulated to revent loss of heat. and. in fact, I prefer to enclose or embed the apparatus in kieselguhr 7. or the like; a box or casing 8 retaining the heat insulating, material 7 in place.

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If the heat exchanging elements are bent into the form of Us, as shown and as preferred, for convenience of manufacture of the parts, assembly, etc.; they may be readily connected in the followlng manner.

The fluid to be heated may be introduced into the device through a pipe 9 which IS in effect a continuation of the tube 2 1n the upper end of oneleg of the first heat exchanging element of the series, as indicated in Figure 1. Said fluid will then flow down and thereafter up through the helical passage 5 within said tube 2, until it emerges into a small U-shaped pipe or connection 10. Connection 10 directs the fluid into the corresponding passage 5 of the next ad acent heat exchanging element, for delivery to a second connection 10, which is, in turn, similarly connected to the third element;- and so on through the respective passages 5, until the now heated gasor other fluid, emerges from the last heat exchanging element of the series, via pipe 11.

The gas or other fluid which is to be cooled, is preferably introduced into passage 4 of said last element,'by means of a pipe 12, which may be directly below pipe 11, as shown in Figure 2; but which is connected immediately into the side of pipe 1 of said last element.

The hot fluid flows helically down and thereafter helically up through the space between pipes 1 and 2 of said element until it emerges laterally through a connection 13. Connection 13 is also preferably U-shaped and delivers the fluid to the next passage 5 of the series, whence said fluid passes via a second connection 13 to the third element of the series, and so on until the formerly hot fluid,now chilled substantially to the temperature of the cold, or relatively cold fluid entering the device through pipe 9,- emerges through pipe 14.

Pumps 15 and 16, respectively connected to the pipes or connections 9 and 14, may be used to promote a flow of fluid through the respective conduits; but, obviously other fluid circulating means may be employed.

In practice this relatively inexpensive, compact and simple construction has proven to be 98% eflicient where two oppositely flowing streams of gas have been caused to exchange heat,one of the streams being initially at, for example, 450 0., and the other at substantially room temperature or lower. The gas can be flowed through rapidly and-the heat loss is, in View of the I extreme efliciency attained, practically negligible. So far as I am aware, it has never been possible heretofore to attain such efficiency with rapidly flowing fluids, in apparatus of this character, even when the heat exchanglng means has been considerably more extensive and correspondingly bulky and costly.

The great efficiency-attained is due in very large measure to the spiral motion imparted to the flowing gas or other fluid WhlCh .prevents what is known in the art as channeling or coring of the gases or liquids;

since centrifu al action always forces the coldest, and of course, heaviest, part of the cold gas out against the inner surfaces of the respective tubes 2, while this same action in the annular spaces between said tubes and the corresponding pipes 1, leaves the hotter portions of the heat supplying fluid immediately in contact with the outer side of these same tubes, and since the tubes are heat conductive, the best possible condition'sfor eflecting a maximum transfer of heat, are established.

Moreover the gases are. flowing through the device in accordance with the counter current principle; and further the means employed tobring centrifugal action into play, are themselves heat conductive.

The twisted members 6 and helical strands 3, hence each perform a plurality of functions, in that they not alone co-act with the tubes to form spirally tortuous passages whereby to compel the fluid flowing in contact with them to spiral and develop the desired centrifugal action, but they further practically prohibit or block any of this fluid from flowing directly past them up or down through the pipes; and they also mechanically cause the fluid to churn or eddy within itself, whereby to effectively mix up the colder portions thereof with the warmer. This. together with the centrifugal action which they establish, practicall eliminates coring. Also, since the coi s are heat conductive, they receive heat from the hot 'fluid and transmit it b to the conductive tubes 2, whicii in turn deliver this heat,as well as that received directly from the hottest parts of the hot stream.--either directly to the colder portions of the cooler stream, or to the ribbons, or their equivalents; which, being also heat conductive, convey it to other and more inwardly disposed portions of said cooler stream.

In addition, the spiral windings of wire, or its equivalent, between the tubes or pipes 1 and 2, keep the inner tubes exactly concentric with the outer ones; which affords great latitude of design; since the assembled inner and outer tubes with thin wrappings and ribbons may be bent into any form desired,as for example, the U-shapes shown; while parts, of any length may be left straight, as in the legs of said Us; and, of course, the so constituted elements can then haveitheir respective passages connected to permit the installation of the desired plurality thereof in assembled relationship to accommodate any space found available between other pieces of apparatus used in the conduction a fluid stream be provided, regardless. of

high' e em ploye his feature is of especial advantage because the apparatus requires practically no attention an itmay hence be installedin limited and more or less normally inacces sible positions.

It is articularly noteworthy that the very fiiciency noted ma be attained even with gases which have igh specific heats,

and this, with a'wide range of gas flows,-

temperatures and pressures.

As previously intimated, however, while i the invention is especially adapted to the treatment of gaseous fluids, it is by no means limited theretoy'nor does it, in its broadest aspects, of necessity involve the transfer of heat to a gaseousor even liquid fluid from another gaseous or. liquid fluid. It is, in

such case, merely essential, generically, that some means of changingthe temperature of whether such means be another and difierently heated fluid or an equivalent of such heatchanging means.

- Having thus described Iclaim is:

1. In an apparatus my invention, what ingdevices connected in series and each comfor exchangingiheat *between fluids, a plurality of heat exchangterial provided with a twisted ribbon-like element for dividing the interior thereof into winding conduits, a spirally wrapped strand upon the outer surface of'said tubular member, asecond tubular member. covering said strand and co-acting therewith to form with said strand and first named member an exterior winding conduit, means for connecting thesaid interior conduits, and means for. connecting the said exterior conduits whereby a flow of liquid may be maintained in both conduits throughout the-several heat exchanging devices.

V 2. In an apparatus for exchanging heat between fluids, a U-shapedheatexchanging .-commnn1eating with said conduit.

In testimony whereof I have afixed my I ,in the presence of two witnesses. a PALMER ST. CLAIR, JR. 'Witnesses: v

M. Josm-H Gomunat, MreHAEnJ. Nooiuar.

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